This application is based upon and claims priority to German Patent Application 100 19 310.2 filed Apr. 19, 2000, which application is herein expressly incorporated by reference.
The present invention relates to a mold with outer mold parts and inserted mold material cores. Together, the outer mold parts and material cores form a mold cavity. The outer mold parts can be part of a permanent mold and/or molding material parts/outer cores.
To produce complicated moldings, such as cylinder heads, it is necessary to insert molding material cores into the outer mold parts. It is also known to use outer molding material cores. Thus, substantial parts of the outer casting faces are not formed by a metallic mold wall. These parts are formed by outer cores of molding material. This method is particularly suitable for casting aluminum and magnesium alloys.
It is an object of the present invention to provide a mold which can be used for complicated castings. In particular, the mold is suitable for rotary casting.
The inner cores including molding material are stacked in layers one above the other. The inner cores are clamped between the outer mold parts and the final covering core of molding material. A continuous force, a going-through uninterrupted force, is applied between the covering core, the inner cores, and the outer mold parts. The mold cavity is formed by surfaces of the outer mold parts, surfaces of the inner cores and the covering core. In accordance with the invention, additional means are not provided to fix the molding material cores in the outer mold cores and to fix the molding material cores between each other. The multi-layer structure enables the production of complicated shapes. By using the final covering core, which is comprised of molding material, it is possible to directly connect a casting container. The covering core preferably comprises at least one ingate aperture and at least one gas exit aperture.
According to a further embodiment, the parts of the mold include a base plate and several side parts. The side parts are movable relative to the base plate. The side parts may include two longitudinal side parts. The longitudinal side parts, relative to the base plate, can be displaced outwardly away from the mold cavity in opposite directions. At least one end side part, relative to the base plate, can be pivoted outwardly away from the mold cavity. This measure enables a problem-free structure of the inner cores, which includes several stacked layers. The inner faces of the side parts may include projections which hold additional individual inner cores relative to the base plate. Displaceable bolts or pivotable claws may be arranged at the base plate or at least at two side parts to secure the covering core. The bolts or claws hold the package of molding material cores within a mold such that, even when the mold rotates, displacements between the inner cores cannot occur.
An inventive mold is used in a particularly advantageous way if the mold is first stacked on the base plate and then rotated by about 180xc2x0 around a horizontal axis. The covering core, which includes an ingate aperture, comes downward to rest. Subsequently, a casting container filled with melt for one casting operation is coupled to the covering core. When the assembly is again rotated by 180xc2x0 around the horizontal axis, the melt flows through the ingate aperture in the covering core into the mold cavity. Thereafter, the melt container is removed and the casting solidifies. After solidification, the mold is removed. The mold is preferably rotated around an axis which extends parallel to the longitudinal extension of the mold cavity.
The base plate is provided in the form of a permanent mold part. Ordinarily, the base plate is metal. The outer mold parts can also be permanent mold parts mechanically connected to the base plate. Also, the outer mold parts can be molding material parts. In this case, mechanical clamping means clamp the parts onto the base plate from the sides and from above. Also, the clamping means is connected to the base plate.
From the following detailed description, taken in conjunction with the drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.